The Effects of Reactant Concentration and Air Flow Rate in the Consumption of Dissolved O2 during the Photochemistry of Aqueous Pyruvic Acid
The Effects of Reactant Concentration and Air Flow Rate in the Consumption of Dissolved O2 during the Photochemistry of Aqueous Pyruvic Acid
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DOI：
10.3390/molecules24061124
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发表时间：
2019-03-02
期刊：
影响因子：
4.6
通讯作者：
Guzman, Marcelo I.
中科院分区：
文献类型：
--
作者：
Eugene, Alexis J.;Guzman, Marcelo I.
有机发色团黄酸（PA）在水中的阳光光化学反应产生酮基和乙酰基自由基，有助于大气气溶胶的产生和处理。光化学机制对溶解氧含量[O-2（aq）]以及其他环境条件高度敏感。因此，在本文中，我们调查的光解（305 nm）的10-200 mM PA在pH值为1.0的水覆盖的相关范围0 [O-2（aq）] 1.3 mM。溶解氧的快速消耗的中间光解自由基监测在真实的时间与溶解氧电极。此外，在空气流量为30.0至900.0 mL min（-1）时，研究了O-2（aq）消耗速率。对于在空气饱和条件下覆盖的[PA]（0）的范围，在该设置中30 mL min（-1）的空气流量，光解自由基消耗的O-2（aq）的估计半衰期落在22至3 min的区间内。因此，O-2（g）渗透到水中的相应深度（x = 4.3和1.6 μ m）的测定，这表明积累和小的粗模式的含水颗粒不应该是O-2-耗尽在阳光的光子撞击这种发色团的存在下。这些光化学的结果是主要的对流层相关的理解二次有机气溶胶的形成和增长。
The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O-2(aq)], among other environmental conditions. Thus, herein we investigate the photolysis ( 305 nm) of 10-200 mM PA at pH 1.0 in water covering the relevant range 0 [O-2(aq)] 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. In addition, the rate of O-2(aq) consumption is studied at air flow rates from 30.0 to 900.0 mL min(-1). For the range of [PA](0) covered under air saturated conditions and 30 mL min(-1) flow of air in this setup, the estimated half-lives of O-2(aq) consumed by the photolytic radicals fall within the interval from 22 to 3 min. Therefore, the corresponding depths of penetration of O-2(g) into water (x = 4.3 and 1.6 mu m) are determined, suggesting that accumulation and small coarse mode aqueous particles should not be O-2-depleted in the presence of sunlight photons impinging this kind of chromophore. These photochemical results are of major tropospheric relevance for understanding the formation and growth of secondary organic aerosol.